Manufacture of corrugated paper



Patented Jan. II, 1938 "MUNITEDSTATES PATENT OFFICE a r 2.1m

-MANUFACTURE OF CORRUGATED PAPER,

' Charles Quincy Ives, Ila-s lllignor to Sherman Paper Products Corporation, N Mine, a corporation of Massachusetts No Drawing. Application m 11. m7, sem s. 1mm

11 Claims. (CI. 92-70) This invention relates to the manufacture of formable with the need of little, if any, moisture corrugated paper products such as are useful for therein as it passes into the nip of the corrugat making cartons or boxes, for wrapping fragile ing rolls, wherefore, the corrugated sheet hereof and otherware, for lining boxes and freight cars, requires little, if any, drying after the corrugat it etc., for which purposes they may be used as log operation. It is generally preferable to pass 5 such or faced on either or both sides with flat the flat starting sheet through corrugating rolls or plane paper adhesively secured thereto. In heated to a temperature of about 300' to 400 making a corrugated paper product, it has here- F. in producing the corrugated paper product tofore beenthe practice tostart with a comparahereof. as the desired incipient fusion of the tively stiff and rattly paper sheet so as to realize leather fiber content of the sheet can be eflected 10 a finished corrugated paper product whose corvery quickly at such temperature while Substanrugations were of sumclent stiffness to resist tially avoiding scorching or other injury to the breakdown or flattening out during handling, cellulosic fibers. storage, and use. 7 The corrugated paper product hereof may be In accordance with the present invention, there fabricated from starting paper sheets of various 1 is provided a corrugated paper sheet or product compositions, but. in any event, it is desirable paper products heretofore produced, the corruner lly s aki the rt n P er h et for gated paper sheet hereof is produced from an the purpose hereof is preferably of a thickness of 85 initially flat paper sheet wherein no attempt has about 0.006 to 0.012", as such a sheet may be 5 necessarily been made to realize high degree of converted by the invention hereof into a finished stiflnessor rattle. as by the introduction of sizing corrugated paper product of th r q s y orstiffening agents thereinto. The starting paper and mechanical properties, including tensile sheet for the corrugated paper product hereof is fltrensth. tear resistance, etc. Because of the characterized byasubstantial content of leather bindins and ifl ln 611 1 of he in ipient y 30 fiber which.although essentially a "dead infused leather fiber content in the finished corgredient in the initially flat paper sheet in the nfl d p p r p d it is nece ary o use or less incipientlyfused by heat during the sheetfurnish to P881129 at 5 Sheet thickness of about 35 sa ns peration so as to exert a very -006 to 0.012" in the finished corrugated paper marked stifl'ening effect in the finished or corru-. P the requisite m i l P perties. The gated paper product a d t th same t to fact is that even the cheapest or waste cellulosic m a high degree of resiliency t the materials, including such waste papers as giassine,

results. An important advantage of the initially papers sometimes termed floor sweepings" flat sheet used herein is that it is readily conj m pap rs.

and about 275 parts of previously shredded or disintegrated tanned scrap sole leather was also added to the beater along with sumcient water to ensure free circulation of the beater charge or contents. The heater charge was beaten or disintegrated for a period of about an hour or more,

with gradual lowering of the beaterroll end of the beating operation so as to ensure a smooth finished stock or papermaking furnish which could be formed into a sheet of the desired, uniform texture on a Fourdrinier. or equivalent paper-making machine. In the course of the beating operation, for instance. at the end stages thereof, it is preferable to add about 20 to 30 pounds of lime to the beater charge for the purpose of facilitating the disintegration or defiberi zation of such residual clumps or pieces of paper, such as waxed paper. that may resist complete defiberization. The lime apparently promotes a dispersion of the wax content of the residual waxed paper pieces and simultaneously, to cause individualization or separation of the fibers constituting such pieces. Again. the lime. evidently by reason of reaction with the leather fibers and/or their content of tanning agent. generates a substantially uniform browncoloration throughout the beaten stock. which coloration is desirable in that thepaper sheet made from the stock has a brown or tannish hue reminiscent of kraft paper and thus attractive to the consumer. Such brown coloration of the stock ensues. irrespective of such varied color waste papers as may constitute the raw material of thebeater furnish; and such coloration is sufilciently potent or dominating to offset or mask the varied colors of the which varied colors, if permitted to persist in the finished paper product. would make .for a heterogeneously or irregularly colored paper of poor or unattractive appearance.

The lime-treated beaten stock is preferably jordaned priorto its delivery to the stock chest of the papermaking machine wherein the stock may be. diluted with water from a beater or Jordan consistency of, say, about 5% to a papermaking consistency of about The stock is formed on the papermaking machine into a sheet of a thickness of preferably about 0.009" and wound up as delivered from the dry end 0! the papermaking machine into parent rolls for transfer to the corrugating machine. a

The paper sheet may be progressively unwound from a parent roll and run through a corrugating machine whose corrugating rolls are internally heated by steam or other suitable heating medium to a temperature of, say, about 340 to 350 1''. As already indicated. it is unnecessary to moisten the paper sheet preparatory to its beingprogressively run through the corrugating rolls maintained at such temperature, since the sheet very nicely assumes the fluted peripheral configuration of the corrugating rolls without any tendency whatever to be embrittled. crushed. or torn in'the flutes or teeth of the rolls. The corrugated sheet progressively issuing from the nip of the corrugating rolls is preferably placed under little tensionor restraint immediately after its issuance from the corrugating nip, but. as it'gradually cools down to room temperature and its incipiently fused leather fiber component and its corrugations stiffen or set, the slack in the sheet may be taken up and the sheet may be accumulated under tension in roll form or, prior to such accumulation. be faced under tension-on either or both sides with a plane paper sheet, which may be adheat the beater engine the cellulosic sively secured to the crests of the corrugations, as ordinarily.

It is to be understood that the principles of the present invention extend to the use of paper sheets made from furnishes containing cellulosic fibers of all sorts and treated or processed otherwise than in the specific example hereinbefore given. Thus. the cellulosic fiber component of the beater furnish may be any one or a mixture of a wide variety of virgin fibers, such as kraft, sulphite, or other chemical wood pulp, mechanical wood pulp. newsprint. rags. etc.: and the leather fiber component of the furnish may be had from scrap ieatherboard. waste leather, or the like, which may be reduced or disintegrated to pulp form in the presence of water in the prior to the admixture therewithof it may be desirableto replace some or most of the cellulosic fiber component of the papermaking furnish with such specific fibers as asbestos and/oi wool in order to impart special or specifically desired properties in the finished corrugated sheet hereof. It ispreferable to use lime as'the promoter of disintegration of refractory papers such as waste waxed paper and as the chemical for generating the tan color throughout the stock by reaction with the defiberized tanned leather scrap and/or its content of tanning agent. In this latfiber component. In some instances.

ter connection. it might be noted that while such stronger alkalies as caustic soda might be used in lieu of lime for such latter purpose. they are more expensive than lime and tend to gelatinize or dissolve the leather fibers and thus to lead to a paper sheet of V brittleness coupled with unduly low tear resistance suchfas give rise to the danger of breakage or rupture of the sheet during the corrugating operation.

I claim:

1. A corrugated paper sheet containing, besides cellulose fiber. leather fiber set from incipiently fused condition and contributing marked stiffness and resiliency to the corrugations of said sheet.

2. A corrugated-paper sheet of a thickness of 0.006 to 0.012 inch and containing. besides cellulose fiber, leather fiber set from incipiently fused condition and contributing marked stifiness and resiliency to the corrugations of said sheet.

3. A corrugated paper sheet containing leather fiber in the amount of about 10% to 50%. based on the weight of the sheet, set from incipiently fused condition and contributing marked stifiness and resiliency to the corrugations of said sheet.

' 4. A corrugated paper sheet of-a thickness of about 0.006 to 0.012 inch and containing leather fiber in the amount of about 10% to 50%, based on the weight of the sheet; set from incipiently [used condition and contributing marked stillness and resiliency to the corrugations of said sheet.

5. A method whichcomprises forming a paper sheet from a papermaking furnish containing. besides cellulose fiber, leather fiber in substantial amount;.and corrugaiing the resulting paper sheet under sufficient heat to cause incipient fusion of said leather fiber.

6. A method which comprises forming a paper unduly high initial stiffness or about 10% to 50% leather fiber, based on the lime into a papermaking furnish containing weight of the solid ingredients of said furnish; anned leather fiber in the amount of about 10% and corrugating the resulting paper sheet at a to 50% by weight of the solid ingredients of said temperature of about 300 to 400 F. furnish, forming a paper sheet from said lime- 5 8. A method which comprises forming a paper treated furnish, and corrugating the resulting 5 sheet of a thickness of about 0.006 to 0.012 inch paper sheet under sumcient heat to cause infrom a papermaking furnish containing about cipient fusion of said leather flbe resulting paper sheet in substantially dry condilime into a papermaking furnish containing es- 10 tion at a temperature of about 300 to 400 F. sentially beaten waste paper and deflberized 10 9. A method which comprises incorporating scrap sole leather, said leather fiber constituting alkali into a paper making furnish containing a about 10% to 50% by weight of the solid ingresubstantial amount of leather fiber in admixture dients of said furnish, forming said lime-treated with cellulosic fiber, forming a paper sheet from furnish into a paper sheet of a thickness of about 15 said alkali-treated furnish, and corrugating the 0.006 to 0.012 inch, and corrugating the resulting 15 

